Stabilized manganese ethylene bisdithiocarbamate and process



United States Patent US. Cl. 424-249 4 Claims ABSTRACT OF THE DISCLOSURE Manganese ethylene bisdithiocarbamate and its formulations stabilized with 1,3,5-tris(cyanomethyl)hexahydrotriazine.

It is known that most metal salts of alkylene bisdithiocarbamic acids are not stable at elevated temperature and this is indicated by evolution of carbon disulfide and a decrease in the fungicidal activity of these materials. These phenomena of instability also occur during long storage.

Manganese ethylene bisdithiocarbamate shows these disadvantages to a greater extent than the corresponding other metal salts. It is also known that manganese ethylene bisdithiocarbamate can ignite spontaneously during its manufacture. Furthermore, other decomposition phenomena have been noted such as discoloration or charring and this occurs especially on storage at elevated temperatures.

Numerous stabilizers for manganese ethylene bisdithiocarbamate have been proposed. In US. patent specification 2,665,285 the use of inorganic sulfites of sodium or calcium is recommended. Thiourea is also known as a stabilizer for an aqueous solution of the manganese salt of ethylene bisdithiocarbamate acid. Both methods, however, require storage free of air.

In German patent specification 1,113,607 (and US. 2,- 974,156) hexamethylene tetramine has been described as a stabilizer for manganese ethylene bisdithiocarbamate in the presence of air. In Dutch patent application 288,- 639 mixtures of several metal salts of propylene bisdithiocarbamic have been described and the unstable manganese salt is shown to be stabilized by other metal salts present. French patent specification 1,344,342 indicates the use of paraformaldehyde as a stabilizer and French patent specification 1,374,622 indicates the use of ortho, meta or para-phenylene diamine for stabilizing manganese ethylene bisdithiocarbamate.

It has now been :found that manganese ethylene bisdithiocarbamate can be stabilized more eflectively than heretofore by using as a stabilizer 1,3,5-tris(cyanomethyl) hexahydrotriazine which compound has the structure CH2ON 1L 0E2 CHg NC-CH2-IIV 1\II-CH2ON and which is described in Beilsteins handbook.

The stabilizing action of 1,3,5-tris(cyanomethyl)hexahydrotriazine has been evaluated by experiments which determine relative ignition periods for manganese ethylene bisdithiocarbamate containing various stabilizers.

In the evaluation procedure, the 1,3,5-tris(cyanomethyl)hexahydrotriazine stabilizer is used in an amount of 2% by weight, based on the dry manganese ethylene bis- 3,436,457 Patented Apr. 1, 1969 dithiocarbamate, and it is added in the form of a 5% by weight solution of equal parts by volume of water and acetone to a paste of the bisdithiocarbamate containing between 20 and 30% by weight of water. The other stabilizers used in the test are added in the same amount as a 10% by weight aqueous solution. After mixing the manganese ethylene bisdithiocarbamate and stabilizer, the mixture is dried at 60 C. under reduced pressure until the water content has been reduced below 0.5 by weight.

Of the sample mixture obtained in this way, 15 grams is introduced into a large test tube and the tube placed in an oil bath maintained at 140 C. After a time, ignition occurs and then the contents of the tube are poured out where glowing and smouldering of the mixture in the air continues. The ignition period, which is the period of heating in the oil bath prior to the beginning of burning, is measured in minutes. Although the method is simple, it is quite reproduceable.

The results of a large number of experiments are shown in Table I which follows:

TABLE I Ignition period in Stabilizer: minutes Control 23 1) o-Phenylenediamine 20 (2) fl-Naphthylamine 20 (3) Monomethylolurea 20 (4) Phenothiazine 23 (5) 2,6-di-tert. butyl p-cresole 23 (6) N-butyl p-aminophenol 27 (7) Pyrogallol 21-30 (8) o-Aminophenol 30-40 (9) Mercaptobenothiazole 31-40 (10) Mercaptobenzimidazole 40-50 (11) 4-methylaminophenolsulfate 40-50 (12) p-Aminophenol 60 (13) Sodium salt of methylamino methanesulfonic acid 60 (14) Hexamethylene tetramine 180 (15) 1,3,5-trinitroso hexahydrotriazine 60 (16) 1,3,S-trimethylhexahydrotiiazine 60 (17) 1,3,5 tris(cyanomethyl)hexahydrotriazine 300 As can be seen from the table, the excellent stabilizing effect of 1,3,5-tris(cyanomethyl) hexahydrotriazine is clearly evident.

A number of experiments were carried out to determine the decrease in manganese ethylene bisdithiocarbamate content during drying and storage of various stabilized compositions. For comparative purposes hexamethylenetetramine, a known stabilizer, was used also. Stabilizers were added to (1) a paste containing about 25% by weight of water and which was obtained by centrifuging an aqueous manganese ethylene bisdithiocarbamate suspension, (2) solid manganese ethylene bisdithiocarbamate containing 2 molecules of water per molecule, and (3) completely anhydrous manganese ethylene bisdithiocarbamate.

The hexamethylene tetramine (HMT) was added as a powder and as a 10% by weight solution in water. The 1,3,5-tris(cyanomethyl)hexahydrotriazine was added as a powder and as a 5% by weight solution in a mixture of equal parts by volume of water and acetone. Where necessary, the mixtures were dried until the water content was below 0.5% by weight. The decrease in the amount of manganese ethylene bisdithiocarbamate after storage of the dried mixtures at C. (atmospheric pressure) after 48 hours and 200 hours, respectively, was determined. In a second test, there was determined the decrease of the manganese ethylene bisdithiocarbamate content due to a combination of drying at 60 C. at 50 to mm. Hg plus storage at elevated temperatures (90 C.) for 48 and 200 hours, respectively. These results are shown in Table II and the values in the tables are based on the arbitrary value of 100 for the decrease of manganese ethylene bisdithiocarbamate content in the absence of stabilizer. The results of the comparative experiments shown in Table II indicate the excellent stabilizing action of the 1,3,5-tris (cyanomethyl)hexahydrotriazine.

The fungicidal action of the stabilized manganese ethylene bisdithiocarbamate either as such or in the form of a formulation is not affected by the addition of 1,3,5- tris(eyanomethyl)hexahydrotriazine.

We claim:

1. Manganese ethylene bisdithiocarbamate and a stabilizing amount of 1,3,5-tris(cyanomethyl)hexahydrotriazine.

TABLE II Amount of Stabilizer Stabilizer stabilizer bzltseg on Folm HMT(S) HMT(P) THT(S) TIIT(P) HMT(S) HMT(P) TIIT(S) TIIItP) (Ill 1y rolls Maueb Mancb Decrease of Maneb content after storage Decrease of Maneb content after storage (percent of Maneb plus stabilizer for 48 hours at of Maneb plus stabilizer for 200 hours at by weight) 90 C. 90 C.

2 39 08 58 50 79 61 1 Maneb 53 88 73 69 93 75 0. Paste 72 100 100 80 95 76 0 100 100 100 100 100 100 2 S1 86 58 66 73 78 71 76 1 Maneb 84 100 63 70 77 85 75 92 (l. 5 2-Hg0 100 100 78 84 94 89 82 93 0 100 100 100 100 100 100 100 100 2 38 44 41 74 48 65 1 Martel) 49 46 47 55 78 51 78 0. 5 D-Hzo 57 60 48 48 57 82 55 79 0 100 100 100 100 100 100 100 100 Decrease of Maneb Content after Drying Decrease of Maneb Content after Drying and Storage for 48 hours and Storage for 200 hours 2 74 53 81 62 1 Maneb 84 89 65 81 94 75 0. 5 Paste 100 100 88 95 77 0 100 100 100 100 100 100 2 100 87 69 66 100 79 78 80 1 Maneb 100 100 76 77 100 84 84 93 0. 5 2-11 0 100 100 84 89 100 90 85 0 100 100 100 100 100 100 100 2 94 52 62 91 84 78 1 Maneb 100 71 63 97 86 89 0.5 O'HQO 100 77 70 100 97 95 0 100 100 100 100 100 100 1 i?\ i' i (S)Hexamethylene tetramine solution. Hltll(P)-Hexamethylene tetramine powder. THT(S)1,3,5-tris(eyanomethyl) hexahydrotriazine solution. THT(P)1,3,5-tris(cyanomcthyl) hexahydrotriaziue powder.

Fungicidal compositions containing the stabilized manganese bisdithiocarbamate may be prepared in the usual way of making fungicidal compositions. The stabilizer together with the manganese ethylene bisdithiocarbamate can be mixed with one or more liquid or solid carriers and, if desired, with one or more of the usual components of fungicidal compositions, such as dispersing, emulsifying and/or wetting agents. The stabilizer can also be added to a prepared composition of manganese ethylene bisdithiocarbamate. The amount of manganese ethylene bisdithiocarbamate in the stabilized composition depends upon the particular end use and may vary from 10 to 90% by weight. When used for the treatment of crops the compositions are generally diluted with suitable diluting agents to obtain the desired concentrations of active ingredients.

The stabilizing amount of 1,3,5-tris(cyanomethyl)hexahydrotriazine will generally be from about 0.1 to about 5% by weight and preferably from 0.5 to 2% by weight based on the manganese ethylene bisdithiocarbamate. It will be understood that greater amounts may be used and these amounts are employed both when stabilizing the bisdithiocarbamate as such and when preparing stabilized fungicidal compositions.

2. A fungicidal composition comprising 10 to 90% by weight of manganese ethylene bisdithiocarbamate and from 0.1 to about 5% by weight of the manganese ethylene bisdithiocarbamate of l,3,5-tris(cyanomethyl)hexahydrotriazine.

3. A process for stabilizing manganese ethylene bisdithiocarbamate which comprises adding as a stabilizer from about 0.1 to about 5% by weight of the manganese ethylene bisdithiocarbamate of 1,3,5-tris(cyanomethyl) hexahydrotriazine.

4. A process for preparing a fungicidal composition containing manganese ethylene bisdithiocarbamate which comprises adding to said composition a stabilizing amount of 1,3,5-tris (cyanomethyl)hexahydrotriazine.

References Cited UNITED STATES PATENTS 2,974,156 3/1961 Sobatzki 260429 TOBIAS E. LEVOW, Primary Examiner.

A. P. DEMERS, Assistant Examiner.

U.S. Cl. X.R. 

